server.cpp Example File

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  #include <QtWidgets>
  #include <QtNetwork>

  #include <stdlib.h>

  #include "server.h"

  Server::Server(QWidget *parent)
      : QDialog(parent)
      , statusLabel(new QLabel)
      , tcpServer(Q_NULLPTR)
      , networkSession(0)
  {
      setWindowFlags(windowFlags() & ~Qt::WindowContextHelpButtonHint);
      statusLabel->setTextInteractionFlags(Qt::TextBrowserInteraction);

      QNetworkConfigurationManager manager;
      if (manager.capabilities() & QNetworkConfigurationManager::NetworkSessionRequired) {
          // Get saved network configuration
          QSettings settings(QSettings::UserScope, QLatin1String("QtProject"));
          settings.beginGroup(QLatin1String("QtNetwork"));
          const QString id = settings.value(QLatin1String("DefaultNetworkConfiguration")).toString();
          settings.endGroup();

          // If the saved network configuration is not currently discovered use the system default
          QNetworkConfiguration config = manager.configurationFromIdentifier(id);
          if ((config.state() & QNetworkConfiguration::Discovered) !=
              QNetworkConfiguration::Discovered) {
              config = manager.defaultConfiguration();
          }

          networkSession = new QNetworkSession(config, this);
          connect(networkSession, &QNetworkSession::opened, this, &Server::sessionOpened);

          statusLabel->setText(tr("Opening network session."));
          networkSession->open();
      } else {
          sessionOpened();
      }

          fortunes << tr("You've been leading a dog's life. Stay off the furniture.")
                   << tr("You've got to think about tomorrow.")
                   << tr("You will be surprised by a loud noise.")
                   << tr("You will feel hungry again in another hour.")
                   << tr("You might have mail.")
                   << tr("You cannot kill time without injuring eternity.")
                   << tr("Computers are not intelligent. They only think they are.");
          QPushButton *quitButton = new QPushButton(tr("Quit"));
          quitButton->setAutoDefault(false);
          connect(quitButton, &QAbstractButton::clicked, this, &QWidget::close);
          connect(tcpServer, &QTcpServer::newConnection, this, &Server::sendFortune);

          QHBoxLayout *buttonLayout = new QHBoxLayout;
          buttonLayout->addStretch(1);
          buttonLayout->addWidget(quitButton);
          buttonLayout->addStretch(1);

          QVBoxLayout *mainLayout = Q_NULLPTR;
          if (QGuiApplication::styleHints()->showIsFullScreen() || QGuiApplication::styleHints()->showIsMaximized()) {
              QVBoxLayout *outerVerticalLayout = new QVBoxLayout(this);
              outerVerticalLayout->addItem(new QSpacerItem(0, 0, QSizePolicy::Ignored, QSizePolicy::MinimumExpanding));
              QHBoxLayout *outerHorizontalLayout = new QHBoxLayout;
              outerHorizontalLayout->addItem(new QSpacerItem(0, 0, QSizePolicy::MinimumExpanding, QSizePolicy::Ignored));
              QGroupBox *groupBox = new QGroupBox(QGuiApplication::applicationDisplayName());
              mainLayout = new QVBoxLayout(groupBox);
              outerHorizontalLayout->addWidget(groupBox);
              outerHorizontalLayout->addItem(new QSpacerItem(0, 0, QSizePolicy::MinimumExpanding, QSizePolicy::Ignored));
              outerVerticalLayout->addLayout(outerHorizontalLayout);
              outerVerticalLayout->addItem(new QSpacerItem(0, 0, QSizePolicy::Ignored, QSizePolicy::MinimumExpanding));
          } else {
              mainLayout = new QVBoxLayout(this);
          }

          mainLayout->addWidget(statusLabel);
          mainLayout->addLayout(buttonLayout);

          setWindowTitle(QGuiApplication::applicationDisplayName());
  }

  void Server::sessionOpened()
  {
      // Save the used configuration
      if (networkSession) {
          QNetworkConfiguration config = networkSession->configuration();
          QString id;
          if (config.type() == QNetworkConfiguration::UserChoice)
              id = networkSession->sessionProperty(QLatin1String("UserChoiceConfiguration")).toString();
          else
              id = config.identifier();

          QSettings settings(QSettings::UserScope, QLatin1String("QtProject"));
          settings.beginGroup(QLatin1String("QtNetwork"));
          settings.setValue(QLatin1String("DefaultNetworkConfiguration"), id);
          settings.endGroup();
      }

      tcpServer = new QTcpServer(this);
      if (!tcpServer->listen()) {
          QMessageBox::critical(this, tr("Fortune Server"),
                                tr("Unable to start the server: %1.")
                                .arg(tcpServer->errorString()));
          close();
          return;
      }
      QString ipAddress;
      QList<QHostAddress> ipAddressesList = QNetworkInterface::allAddresses();
      // use the first non-localhost IPv4 address
      for (int i = 0; i < ipAddressesList.size(); ++i) {
          if (ipAddressesList.at(i) != QHostAddress::LocalHost &&
              ipAddressesList.at(i).toIPv4Address()) {
              ipAddress = ipAddressesList.at(i).toString();
              break;
          }
      }
      // if we did not find one, use IPv4 localhost
      if (ipAddress.isEmpty())
          ipAddress = QHostAddress(QHostAddress::LocalHost).toString();
      statusLabel->setText(tr("The server is running on\n\nIP: %1\nport: %2\n\n"
                              "Run the Fortune Client example now.")
                           .arg(ipAddress).arg(tcpServer->serverPort()));
  }

  void Server::sendFortune()
  {
      QByteArray block;
      QDataStream out(&block, QIODevice::WriteOnly);
      out.setVersion(QDataStream::Qt_4_0);

      out << fortunes.at(qrand() % fortunes.size());

      QTcpSocket *clientConnection = tcpServer->nextPendingConnection();
      connect(clientConnection, &QAbstractSocket::disconnected,
              clientConnection, &QObject::deleteLater);

      clientConnection->write(block);
      clientConnection->disconnectFromHost();
  }